In some rotorcraft, the rotor blades are coupled to a yoke that is attached to a rotating shaft. Torque generated by the rotating shaft is transferred to the yoke and blades by the coupling between the yoke and the shaft. In some instances, the yoke can be tilted with respect to the shaft during rotation. In some cases, the coupling between the yoke and the shaft can provide constant velocity torque transfer even as the yoke tilts with respect to the shaft.